BIOLOGICAL REGENERATION OF PARA-NITROPHENOL LOADED ACTIVATED CARBON

Biological regeneration is one of several methods that may be used to restore the adsorptive capacity of exhausted granular activated carbon (GAC). This study deals with in-situ biological regeneration on a pilot scale.The principal objective of this research was to ascertain whether biological regeneration of GAC could occur under conditions typical of water treatment. The important parameters which may have the greatest impact on bioregenerationfor a given adsorbate were studied. The research investigated the extent of bioregeneration for para-nitrophenol ( PNP )of concentration 50 mg/l. Bioregeneration in the total exhaustion system was evaluated in terms of regeneration efficiency and the substrate removal. A three mode procedure was followed for each bioregeneration run. The prepared carbon was initially exhausted with an adsorbate; it was then bioregenerated with a mixed culture of bacteria, and lastly the carbon was resaturated. In the totally exhausted GAC system, the bioregeneration was enhanced by increasing the duration of regeneration for a fixed initial biomass content of the bioreactor.The bioregeneration efficiency of the totally exhausted ( with PNP ) GAC the empty bed contact time ( EBCT ) and the initial concentration of the substrate had a profound effect on the bioregeneration efficiency. Bacterial counts in the effluents of regenerated GAC columns were significantly more than those of fresh carbon effluents